Makes PhoneNumberUtils support international numbers after a CLIR command.

Makes PhoneNumberUtils.java support numbers in international
format (starting with ‘+’ character) after a CLIR command.

Previously a plus character would always be removed unless it
occupied the first position of the number string. In this case,
when the number is preceded by #31# (CLIR), the plus character
will be removed as well.

This is an error, prohibiting a type approval of the phone.

This change will detect the plus character after the CLIR command
and will insert it at the right position.

Change-Id: Ib220aee7b3eda30cde960db8c7470523dc5fd313